Saddle block for power shovel



y 4, 1962 T. LEARMONT ETAL 3,045,844

SADDLE BLOCK FOR POWER SHOVEL Filed March 17, 1959 2 Sheets-Sheet 1 INVENTORS Tom LEARMONI' Rosem- E.TA\ \.Ev

ATT'O EY July 24, 1962 T. LEARMONT ETAL SADDLE BLOCK FOR POWER SHOVEL Filed March 17, 1959 2 Sheets-Sheet 2 FIG. 4

INVENT ORS TOM LEARMONT RDBERT E. TAU-EV ATTORNEY United States Patent ()fllice 3,945,844 Patented July 24, 13 62 3,945,844 SADDLE ELGCK Fill POWER SHOVEL Tom Learmont, .Wauwatosa, and Robert E. Talley, Racine, Wis, assignors to Eucyrus-Erie Company, Milwaukee, Wis, a corporation of Delaware Filed Mar. 17, 1959, Ser. No. 7%,987 8 Claims. (Cl. 214135) This invention relates generally to the saddle block of a power shovel in which an outwardly extending dipper handle is mounted for rotational movement about its longitudinal axis as well as reciprocab'le movement along that axis.

It particularly relates to an energy-absorbing snubbing mechanism to restrain such rotational movement after a predetermined limit of movement has been reached.

In some power shovels it is desirable to mount the dipper handle in the saddle block in such a manner that the dipper handle is free to rotate about its longitudinal axis. With such a mounting, any rotation of the handle during the digging cycle does not result in torsional stresses in the saddle block or the boom. Such a mounting also permits the dipper to seek a position of equilibrium dur ing loading operations so that the lifting forces required at each side of the dipper will balance the digging loads 7 encountered by the respective sides of the digging edge of the dipper. To assist the dipper in reaching and maintaining such a position of equilibrium, separate hoist ropes may be provided at each side of the dipper.

In power shovels, a means is usually provided for the purpose of crowding and retracting the dipper handle along its longitudinal axis; in certain constructions, cables or ropes are used and are attached to the dipper handle in closed-circuit relation. Consequently, any rotation of the dipper handle beyond certain limits is undesirable, since excessive rotation will interfere with and cause damage to the crowd and retract means.

During lowering of the empty dipper, the dipper handle is often caused to rotate about its longitudinal axis by the bottom or a corner of the dipper striking a projection, such as a rock in the digging face of material being excavated. At times, the resulting rotational movement of the dipper handle greatly exceeds the limits required to maintain the dipper in a position of equilibrium during loading; on some occasions the rotational movement is great enough to damage the crowd and retract means. Also, excessive rotation of the handle may be induced by digging resistance encountered at the corner of the dipper during the start of a digging cycle, especially when the dipper has been positioned near the foot of the boom and the hoist ropes are almost parallel to the dipper handle.

Accordingly, it is a principal object of the present invention to provide a saddle-block mounting for a dipper handle with a snubber mechanism which will permit free rotation of the dipper handle within a predetermined range of movement and restrain any further movement beyond that predetermined range.

It is undesirable to use a positive stop, such as a solid, noncompressible block, to limit the rotation of the dipper stick because of excessive impact loads which would be encountered in the massive constructions of present day power shovels. It would also be undesirable to use a compressible, energy-storing type of stop, such as a spring, which would not absorb and dissipate the energy of the rotating dipper handle but would store the energy and then rebound. A compressible, energy-storing means would thus tend to cause a positive return of the dipper handle, as well as consequent oscillation which is objectionable.

Therefore, it is a further object of the invention to provide a saddle-block mounting for a dipper handle with an energy-absorbing snubber mechanism which will permitfree rotation of the dipper handle about its longitudinal axis within a predetermined range of movement and will be effective to absorb any energy causing rotation of the handle beyond said range.

A still further object of the invention is to provide a snubber mechanism associated with a saddle-block mounting for a dipper handle which will restrain rotation of the handle about its longitudinal axis beyond a predetermined range of movement and will not cause any rebound, or positive return, of the handle to that predetermined range.

In addition to the objects above stated, a number of novel and useful details have been worked out which will be readily evident as the description progresses.

The invention consists in the novel parts and in the combination and arrangement thereof which are defined in the appended claims and of which two embodiments are exemplified in the accompanying drawings which are hereinafter particularly described and explained.

Throughout the description the same reference number is applied to the same member or to similar members.

FIGURE 1 is a side elevation of a power shovel embodying the invention.

FIGURE 2 is a plan view of the boom, handle and ropes, taken along the line 22 of FIGURE 1.

FIGURE 3 is a side elevation of the saddle block and snubbing mechanism mounted thereon.

FIGURE 4 is a cross-sectional view taken on line 4-4 of FIGURE 3.

FIGURE 5 is a side elevation similar to FIGURE 3 but showing a second embodiment of the snubbing mechamsm.

FIGURE 6 is a cross-sectional view taken on line 6-6 of FIGURE 5.

Referring to FIGURES 1 and 2, it will be seen that 11 is the propelling base of a power shovel, on which is mounted a'revolving frame 12. A boom 13 is pivotally connected to the frame at 14-. The frame also carries a boom hoist winch 15, a dipper hoist winch 16 and a dipper thrusting winch 17.

Winch 15 manipulates boom suspension cables 18 to and back over another of the sheaves 21 tothe winch 16. V

The dipper 20 is carried on the outer end of a tubular handle 23, which slides and rotates in a saddle block 24, to behereafter described. Winch 17 manipulates thrust rope 25, attached to the rear end of handle 23, and retracting rope 26, attached to the front end of handle 23; both of these ropes may be a portion of a single rope manipulated by winch 17, attached to handle 23 and arranged in a closed circuit relation to provide the thrust and retract means for the dipper handle.

Turning now to FIGURES 3 and 4, it can be seen that the saddle block 24 is mounted on the boom 13 in a conventional manner for rocking movement about a shipper shaft 27. A pair of supporting lugs 28 project from a central portion 29 of the saddle block, and each of the lugs 28 is provided with a cylindrical bore to receive a bearing sleeve 30 in which the handle 23 is reciprocally supported. A radially projecting thrust flange 31 is received in a complementary annular groove 32 in lug 28 to maintain the sleeve MD in the proper relative position While permitting reciprocable movement of the handle.

A radially-projecting key 33, affixed to dipper handle 23 and extending the effective length of the handle, is

antenna loosely received in a longitudinal groove 34 provided in bearing sleeve 30. The relative circumferential dimen- Sions of both the key 33 and groove 34 are such that limited rotation of dipper handle 23 about its longitudinal axis is permitted before the key will contact either side of the groove to cause the sleeve to rotate with the handle. As will be explained below, a snubber mechanism is operatively connected to the sleeve 33, therefore the lost motion connection between the key 33 and the groove 34 will permit free rotation of dipper handle 23 within a predetermined range of movement. This is desirable during loading operations so that the dipper can reach a position of equilibrium in which the lifting forces required at each side of the dipper will be balanced with the digging loads encountered by the respective sides of the digging edge of the dipper. The twin hoist ropes 19 attached to each side of the dipper assist it to reach and to maintain a position of equilibrium during loading. Accordingly, free rotation of the dipper handle about its longitudinal axis within a predetermined range of movement, which is required to allow the dipper to reach such a position of equilibrium, is permitted by the lost-motion connection of the present saddle-block construction.

However, during rapid lowering of thedipper, any object which is projecting from the digging face of the excavating area and which strikes 'a corner of the dipper or any point on the bottom of the dipper which is laterally spaced from the longitudinal axis of the dipper handle will cause rotation of the dipper 20 and handle 23 about that axis. To restrain such rotation beyond the above-described predetermined range of movement, an energy-absorbing snubber mechanism 35 is provided on lug 28 and operatively connected to handle 23 by means of sleeve 30 through the lost motion connection of the groove 34 and key 33.

The snubber mechanism shown in FIGURES 3 and 4 comprises a brake plate 36 rotatably mounted on lug 28 by means of retaining bolt 37 carried in a bracket 38. The brake plate 36 is provided with peripheral teeth which mesh with similar teeth provided on bearing sleeve 30. Thus any rotation of sleeve 30, caused by rotation of handle 23 beyond the aforementioned predetermined range, will result in rotation of brake plate 36. To resist this rotation, friction members 39 are disposed on opposite sides of brake plate 36 and are held in contact with the brake plate by means of pressure plate 40. The pressure plate 40, friction members 39 and brake plate 36 of the brake assembly are held in contact with the adjoining component by means of the retaining bolt 37 received in apertures provided in each of the components. The bracket 38 serves as a reaction member for the snubber mechanism. An adjustable preloading force for the pressure plate 40 is provided by a spring 41 which is compressed by bolt 37.

With this construction, any rotation of dipper handle 23 about its longitudinal axis beyond the predetermined limits of the lost motion connection of key 33 and groove 34 will cause sleeve 30 to rotate with handle 23. Since brake plate 36 f snubber 35 is drivingly connected to sleeve 33, any rotation of handle 23 beyond said predetermined limits will be restrained by the interaction of friction members 39 and brake plate 36 which have been preloaded as described above. The energy causing such rotation will be absorbed by the snubber and dissipated as heat. The snubber will thus restrain the rotation of the handle but will permit sufficient rotation to absorb the energy imparted to the dipper handle by shock loads encountered at a corner or side of the dipper.

The handle 23, having once been rotated from the normal position shown in FIGURE 1, will be returnedto that normal position as a subsequent digging cycle is started; if the handle is rotated at any point during the digging, subsequent action of the twin hoist ropes as the cycle is completed will return the dipper and handle 4 to a normal position. Consequently, any rebound and oscillation of the dipper handle, which might be caused by using a spring or other energy-storing device to limit the rotation of the handle, is Prevented.

In the second embodiment shown in FIGURES 5 and 6, the dipper handle 23 is mounted in similar bearing sleeves 30; however the longitudinal internal groove 34 of sleeve 30 is dimensioned in relation to the key 33 affixed to the dipper handle to provide a suitable bearing clearance rather than a lost-motion connection. An arm 42 projects from the bearing sleeve 30 and is in a substantially vertical position when the dipper is in its normal position (i.e., with the cutting edge of the dipper substantially parallel to the ground supporting the shovel). Mounted on brackets 38 secured to lugs 28 of the saddle block, are energy-absorbing snubber mechanisms 35 in the form of a pair of single-acting hydraulic shock absorbers, the details of which are well known to those skilled in the art. The shock absorbers are mounted and located on the saddle block so that the ends of their operating piston rods 43 are spaced a predetermined distance from the actuating arm 42. Thus a lost-motion connection is provided between the dipper stick and the energy absorbing snubber means, which will permit free rotation of the dipper handle within a predetermined range.

Further rotation of the dipper handle beyond the limits of the lost-motion connection between arm 42 and piston rod 43 will result in actuation of the shock absorber as rod 43 is moved by arm 42. Further rotation of the dipper stick 23 will be restrained at that point, and the energy of the rotating dipper and dipper stick will be absorbed by the snubber mechanism 35 and dissipated as heat. As in the case of the first embodiment, the dipper and dipper handle will be returned to a normal position by gravity and the action of the twin hoist ropes, without any objectionable rebound or oscillation.

Having now described and illustrated one form of the invention, it is to be understood that this invention is not to be limited to the specific form or arrangement of parts herein described and shown.

What is claimed is:

1. In a power shovel, the combination of: a base; a boom inclined forwardly therefrom; a shipper shaft transversely mounted on the boom; a saddle block supported by the shipper shaft for rocking movement; a forwardly extending dipped handle; means carried in said saddle block supporting said handle for rotative movement about the longitudinal axis of said handle as well as reciprocating movement along said axis; and energy-absorbing snubber means carried by said saddle block and operatively connected with said handle to restrain said rotative movement of said handle.

2. In a power shovel having a base; a boom inclined forwardly therefrom; a shipper shaft transversely mounted on the boom, a saddle block supported by the shipper shaft for rocking movement; and a forwardly extending dipper handle supported in the saddle block for rotative movement about the longitudinal axis of the dipper handle; energy-absorbing snubber means carried by 'the saddle block and operatively associated with said wil terized by the fact that the snubber means comprises a pair of single-acting, hydraulic shock-absorbers mounted on the saddle block in such a manner that each of said shock-absorbers will restrain rotation in a direction opposite to the other.

5. In a power shovel having a base; a boom inclined forwardly therefrom; a shipper shaft transversely mounted on the boom; a forwardly-extending dipper handle; and a dipper carried on the outer end of said handle; a saddle-block mounting for said handle comprising: a central portion connected to said shipper shaft for rocking movement; a lug projecting from said central portion and having a generally cylindrical bore, the longitudinal axis of which is substantially parallel to the longitudinal axis of said handle; a bearing sleeve rotatably received in said bore and supporting said handle; a lost-motion connection between said handle and said sleeve to permit free rotation of said handle about its longitudinal axis within a predetermined range of movement; energy-absorbing snubber means carried on said saddle block; and a driving connection between said sleeve and said snubber means whereby rotation of the handle beyond said predetermined range is restrained by the snubber means.

6. In a power shovel having a base; a boom inclined forwardly therefrom; a shipper shaft transversely mounted on the boom; a forwardly extending dipper handle; and a dipper carried on the outer end of said handle; a saddle block mounting for said handle comprising: a central portion connected to said shipper shaft for rocking movement; a lug projecting from said central portion and haw'ng a generally cylindrical bore, the longitudinal axis of which is substantially parallel to the longitudinal axis of said handle; a bearing sleeve rotatably received in said bore and supporting said handle; a driving connection between said handle and said sleeve whereby the sleeve is rotated about its longitudinal axis with the handle; energy-absorbing snubber means carried on said saddle block; and alost-motion connection between said sleeve and said snubber means to permit free rotation of said handle within a predetermined range of movement and to restrain further rotation beyond said range.

7. In a power shovel, a combination of: a base, a boom inclined forwardly therefrom; a shipper shaft transversely mounted on said boom; a saddle block pivotally mounted on said shipper shaft for rocking movement about the axis of said shaft; bearing means carried by said saddle block for supporting said handle for rotative movement of said handle about the longitudinal axis of said handle as Well as reciprocating movement of said handle along said axis; energy absorbing means mounted on said saddle block and engageable with said bearing means; and means for operativelyconnecting said handle and said bearing means for rotational movement therebetween; whereby said energy absorbing means restrains said rotative movement of said handle.

8. The combination of claim 7 wherein the bearing means includes a sleeve for said handle, and the said means for operatively connecting said handle and said bearing means includes a key integral with said handle engageable with a groove of larger extent than said key in said sleeve, whereby free rotation of said handle is permitted within a predetermined range of rotational movement of said handle.

References Cited in the file of this patent UNITED STATES PATENTS 1,954,119 Darrah Apr. 10, 1934 1,962,516 Mitchell June 12, 1934 2,308,966 Saurer Jan. 19, 1943 FOREIGN PATENTS 737,409 Germany July 13, 1943 

